Work-piece ejector for coining presses



Septll, 1962 F. MARTINDELL PIECE EJECTOR FOR COINING PRESSES WORK- 6 Sheets-Sheet 1 Original Filed May 2, 1957 FRANK MARTINDELL Sept. 11, 19 2 F. MARTINDELL WORK-PIECE EJECTOR FOR comma PRESSES 6 Sheets-Sheet 2 Original Filed May 2, 1957 INVENTOR FRANK MARTINDELL ATTORNEY Sept. 11, 1962 F. MARTINDELL WORK-PIECE EJECTOR FOR COINING PRESSES 6 Sheets-Sheet 3 Original Filed May 2, 1957 R m m M 65 FRANK MARTINDELL ATTORNEY Sept. 11, 1962 F. MARTlNDELL PIECE EJECTOR FOR comma PRESSES WORK- 6 Sheets-Sheet 4 Original Filed May 2, 1957 INVENTOR FRANK MARTINDELL ATTORNEY Se t. 11, 1962 F. MARTINDELL WORK-PIECE EJECTOR FOR comma PRES-SE8 Original Filed May 2, 1957 6 Sheets-Sheet 5 INVENTOR FRANK MARTINDELL Sept- 11, 1 F. MARTINDELL WORK-PIECE EJECTOR FOR comma PRESSES 6 Sheets-Sheet 6 Original Filed May 2, 1957 INVENTOR FRANK MARTINDELL ATTORNEY Claims. (or. 7841) The present invention relates to improvements in coining presses and more particularly to an improved workpiece ejector therefore and is a division of my copending application Ser. No. 656,603 which has matured into United States Patent No. 2,910,898.

In coining press-operations, and in some embossing press-operationsas distinguished from punching, drawing, cutting, blanking and/or forming press-operationsvery great pressures are employed to cause the material of the work-piece, being coined (such as metal, plasticresins or the like), to flow within and between the matrix surfaces of opposing closed dies. In late years the side walls of at least one die (usually the lower) are straight and therefore are not relieved or tapered to allow easy removal of the work-piece; and, when these dies are separated, the work-piece is tightly bound or swagged in one die (usually the lower or bed die) and is most difficult to remove without injury to the work-piece. This difificulty has gradually increased over the years and has been greatly intensified since the advent of powdered metallury (in the making of bushings for instance) and especially in the more recent coining of resinous-plastic materials. In such instances, the old practices and devices, previously employed, as knockouts, are inadequate. The mere application of greater force or pressure to the ejectorpad often injures the formed work-piece and projects it at great speed from the die.

Because of these difiiculties and the peculiarities of coining operations, which are almost invariably performed on, so-called, toggle or knuckle presses, there has been a long felt need for an adequate work-piece ejector for such coining presses which will eject the work-piece eflicaciously with a minimum of damage and injury there to and which may be conveniently adjusted to vary the length of the ejecting stroke without reducing the force below that required to properly eject the work-piece or disturbing the timing of the usual automatic work-piece feeding mechanism.

I have found that by employing a toggle-joint linkage to actuate the ejector with a pull-force in its ejecting stroke, upon the breaking or angulation of this linkage from its normal straight position, a maximum high force is applied initially upon the work-piece to break its bond with the die and, as this linkage angulates farther, this force progressively decreases so that the work-piece will not be shot at great speed from the die but is more gently urged from the same without injury to the work-piece. I have also found that by actuating the knee of the togglejoint linkage by a to-and-from movable member, which is adjustable toward and from said knee, the extent of the angulation of the linkage, from its straight line position, may be varied to alter the length of the ejection-stroke to meet the necessary requirements without reducing the application for any given Work-operation of the press and which adjustment assures a constant end-point cut-ofl? of the ejection-movement or stroke.

The main object, therefore, of this invention is to provide a novel work-piece ejector or knock-out mechanism for coining-presses which is of a compact construction embodying the above stated discovery and so designed as to be mounted under and to the bed of such press and aesarzz Patented Sept. 11, 1962 actuated from the ram of the press; and wherein the ejector consists of a reciprocably mounted guide carriage carrying a knock-out pad and a toggle linkage suspending said carriage in its inoperative position, when the linkage is straight (or on dead center), the carriage being operated in its ejection stroke toward the bed of the press, when said toggle linkage is broken or angulated from its straight position by a suitable means, thus applying a high maximum pressur force on the work-piece at the beginning of the ejection stroke which force is reduced progressively thereafter as the angulation continues.

Another object of this invention is to effect the angulation of said toggle linkage by a camming member, preferably an oscillatory cam, having a dwell, mounted for adjustment toward and from the knee of the toggle linkage, with which it engages, to vary the degree of angulation of said linkageand hence the length of the ejection stroke of the carriage and its knock-out pad, thus assuring a constant cut-off or end-point of ejection and facilitating any required adjustment of the timing of the work-piece feeding means.

A further object and advantage of the present ejector means is that it may be arranged vertically so that the ejector may be withdrawn to its inoperative position by gravity, under the weight of the toggle means assuming its straight position, without the need of additional actuating mechanism for this purpose.

A still further object of the invention is the provision of a toggle coining press having such a toggle actuated ejector, as just described, which possess a relatively simple and inexpensive construction, yet rugged to endure the tremendous pressure under which the press operates in the performance of its work and which may be quickly adjusted to best meet the requirements of the particular work to be done, thus increasing the output of the press.

To attain these objects and advantages, as well as other objects as will appear, the invention consists of the features of novelty in substantially the construction, combination and arrangement of the several parts hereinafter more fully described and claimed.

In the drawings, which show, by way of example, one embodiment of the invention as at present devised:

FIGURE 1 is an elevation of the front side of a coining press equipped with the present invention;

FIGURE 2 is an elevation of the rear side of the coining press shown in FIGURE 1 and equipped with the present invention;

FIGURE 3 is a side elevation of the coining press, looking from the right-hand side of FIGURE 1;

FIGURE 4 is an enlarged vertical sectional view taken substantially on line 8-8 of FIGURE 2 and illustrating certain details of the work-piece ejector with the ram or tool-slide in its lowermost position and acting on the work-piece in the die on the bed of the press and with the ejector in its lowered or inoperative position;

FIGURE 5 is a view similar to FIGURE 4 and showing the ram or tool-slide in its raised position and the position of the operating parts of the ejector ejecting the work-piece from the die;

FIGURE 6 is a transverse sectional view taken substantially on line 10-10 of FIGURE 5 to illustrate further details of construction and location of parts; and

FIGURE 7 is a transverse sectional view taken substantially on line 1111 of FIGURE '5.

The coining-press here shown is a, so-called, vertical column toggle press, wherein a press bed 10 is elevated from and suitably anchored to a foundation or floor 11; and, from the opposite ends of said bed, arise columns 12 and 13, forming the side frames of the press, upon the upper ends of which a crown 14 is supported and spans said columns, thus overlying said bed. Tie rods 15 pass through said columns and have their opposite ends extending through openings in said crown and bed, respectively, at their four corner portions, the extremities of said rods being threaded to receive nuts 16, which bear against the crown and bed to tie and hold the parts of the frame in fixed relation to each other.

, A ram or tool-slide 17 is disposed between and mounted in suitable guideways 17*- on the columns 12 and 13 for vertical reciprocation and is supported from the crown 14 and actuated by a toggle-linkage 18 (sometimes called a knuckle-joint), although other suitable means may be employed. The upper end a of this supporting connection 18 is suspended from the underside of a bearing-block 20 by means of a pivot pin 19. The bearingblock 20 is disposed in juXta-relation with the underside of that portion of the crown 14 overlying the ram 17 and has its end portions slidably mounted in guideways 21 carried by the side frames 12 and 13, so that said bearing block 20 may be adjusted to vary the position of the pivot pin 19 vertically relative to the bed 10.

The stroke of the ram 17 may be varied or adjusted by a mechanism indicated at R (FIGS. 1, 2 and 3) which is fully described in my US. Patent No. 2,910,898.

The ram or tool-slide 17 is actuated by an electric motor 32 mounted on top of the crown 14 and which drives a clutch-brake mechanism 33 mounted on a back shaft 34 journal'led on the side frames 12 and 13. A pinion 35 fast to the shaft 34 meshes with gear 36 fast on crank-shaft 37 extending across the back of the press frame (see FIGS. 2 and 3) and also journalled on side frame members 12 and 13.

A pitman-rod 38 connects to the crank of the crankshaft 37 to the center pivot c of the toggle linkage 18 and the lower link of said linkage is pivoted at b to the top of the ram or tool-slide 17', whereby the latter is reciprocated in its guideways 17 so that the tool or die T may be moved to-and-fro relative to the work-piece W in or on the holder or die D supported by the press-bed 16.

After the work-piece W has been shaped, formed or otherwise worked upon by the tool or die T or D, it is ejected automatically from the die or holder D on the bed, after the ram or tool-slide has receded suificiently, by the improved ejector mechanism E shown in detail in FIGURES 4, 5, 6 and 7 and shown in elevation on the press in FIGURES 1, 2 and 3.

As shown, the ejector mechanism or unit E is positioned under and depends from the under surface of the bed by means of suspended bolt rods 40 which pass through the four corners of the suspended frame structure 41 of the ejector. A ram or carriage 42 is disposed within and mounted in guideways 43 and 44 on the frame 41 for to-and-fro vertical slidable movement in the guideways relative to the bed 10. The carriage 42 is preferably of a hollow rectangular frame within which is arranged its operating toggle-linkage L to provide a compact construction of few parts readily actuatable from the crankshaft 37.

The carriage 42 has on its top-cross-piece a knockout pad 45 positoned to align with the holder or die D, supported in the usual manner on the press-bed 10, to be either projected into or through a suitable opening in said bed or to contact and push ejector pins 46 (sometimes carried by the holder or die on said bed) as the exigencies of the particular Work being done may require. The pad 45 has a depending threaded stern 45 threadedly extending into a threaded aperture 42 in the top cross-member of the carriage 42 in order that the pad may be properly adjusted, relative to the work to be performed, by an implement inserted in openings 45' therein. A portion of the aperture 42 is fashioned, as shown in FIGS. 1, 4 and 5, to provide a split clamp-ring 47 partially integral with the carriage 42 so that the stem 45 may be clamped in its adjusted positions.

The toggle-linkage L prefer-ably comprises a pair of spaced and coextensive links 48 and a similar pair of links 49, each pair of links having their adjacent overlapping ends pivotally connected by a common pivot pin 50, upon which is journalled a roller 51 centrally disposed between the overlapping ends of said pairs of links. The other or upper ends of the pair of links 48 are mounted for pivotal movement on a cross-pin 52 having its ends mounted in bearing-openings 52 in opposite side members of the ejector frame 41 (see FIGS. 1, 2 and 6), said end portions of said cross-pin 52 extending through elongated slots 42 in the opposite side members of the carriage 42 so as to allow for the to-and-fro movement of the carriage. The other or lower ends of the pair of links 49 are mounted for pivotal movement on a cross-pin 53 having its ends mounted in bearing openings 53 at the lower ends of the opposite side members of the carriage 42 (see FIGS. 4, 5 and 7). With this arrangement, the pad 45 is moved toward the bed 10 to effect the ejection of the work-piece W from the die or holder B, when the toggle-linkage L is broken as shown in FIG. 5-or, in other words, when the linkage is not in its normal straightened position as shown in FIG. 4-whereby the carriage 42 is moved upwardly by said linkage toward the bed 10; and this movement of the toggle linkage L is accomplished by a cam member 54 actuated in timed relation with the movement of the ram or tool-slide 17.

The cam member 54 preferably comprises an oscillatory segmental member pivoted intermediately of its ends, as at 55, and disposed between and intermediately of two links arms 56 pivotally mounted at one of their ends, as at 56, to brackets 57 on the ejector frame 41, and this cam member is so positioned as to have a camrning portion, beyond its pivot 55, extend into the frame 41 of the ejector unit so that an edge portion of the member 54 will engage and bear against the roller 51. The portion 54 of said edge of the cam member 54 is on a gradient radii, with respect to pivot 55, to provide the effective camming surface and the succeeding adjacent portion 54* is on a uniform radii to provide the dwell of the camming surface at the end of the effective movement of the cam 54. The other portion of the cam member 54, on the other side of the pivot 55, is pivotally connected at 58 to one end of an extensible connecting rod 59, the other end of said connecting rod being connected, as at 37 to the crank of the crank shaft 37. This connection of the connecting rod 5? with the crank shaft 37 is such that flie cam member 54 is oscillated by the movements of the crank shaft 37 so as to cause the cam surface 54 to break or angula-te the toggle linkage L from its position shown in FIGURE 4 to move the pad carriage 42 toward the bed 10, when the ram or tool-slide 17 has receded sufficiently upward from the bed. This results, first, in the forceful breaking of the bond or grip of the workpiece with the walls of the die D and then urges the workpiece with less force from the holder or die D; and, thereafter, the carriage 42 drops by gravity, from its position shown in FIG. 5 to the position shown in FIG. 4, returning the ejector pad 45 to its normalposition between the effective work-performing strokes of the ram or toolslide 17.

The other or lower ends of the link arms 56 are connected to a cross-head 60 which has an intermediate portion formed with a passage through which slidably extends a threaded rod 61 pivoted at one end, as at 62, to a cross-pin 63 mounted at its ends in the frame 41. Jam or locking nuts 64 and 65 are threadedly disposed on the threaded rod 61 at opposite ends respectively of the crosshead 60 so as to maintain the cross-head 60 in its ad' justed positon on the threaded rod 61.

The length of the toand-fro movement of the carriage 42 carrying the pad 45 may be varied by the position of the cross-head 60 on the rod 61, as this adjustment shifts the axis of the cam member 54. Therefore, it is clear that, by shifting the crosshead 60 to the right on the rod 61 (by suitable adjustment of the nuts 64 and 65), the center distance of the pivot 55 from the roller 51 is increased, thereby reducing the effective operation of the cam surface 54 upon the linkage and, hence, the extent of angular movement of the toggle links 48 and 49, thus reducing the distance of travel or movement of the carriage 42 and its knock-out pad 45; and it is also clear that the converse is true. Where necessary to coordinate this shifting of the cam with respect to the timing of the dwell, this can be compensated by suitable adjustment of the extensible connecting rod 59.

Since the toggle-linkage L is always in a straight-line position, as in FIG. 4, at the beginning of the ejecting stroke of the ejector pad carriage 42, the force exerted is at its maximum at this point, and, since the dwell 54 always occurs at the end of the ejection stroke, the endpoint of the ejection movement is always constant, which is advantageous in the timing of feeding mechanism (not shown) for the press.

When the ejector E of this invention is used in a vertical position, as shown in the drawings, no additional means is necessary for returning the carriage to its normal position, retracted from the bed 16, as shown in FIG- URE 4, because the particular construction herein employed permits the weight of the carriage 42 to drop by gravity, thus bringing the toggle linkage L to its straightline normal position.

However, should positive means he desired to return the carriage 42, this has been done by mounting an air cylinder under the bed, which is coordinately controlled to return said carriage to its normal position.

The ejector mechanism E therein shown and described may have other applications of use but is particularly useful and desirable when employed in combination with coining-presses as therein described.

From the above, it should be clear that a device constructed in accordance with this invention as herein shown and described attains all of the objects aforementioned with their attendant advantages. While the preferred form of the invention has been shown and described herein, it is to be understood that various changes may be made in details of construction and in the combination, arrangement and organization of the several parts without departing from the spirit of this invention and that the invention is only to be limited by the scope of the appended claims.

That which is claimed, as new and to be secured by Letters Patent, is:

1. A work-piece ejector for a heavy-duty die-stamping press, particularly of the coining type having a die-supporting bed and a die-rain movable to and fro relative to the bed-die, the improvement comprising an ejectorframe adapted to be disposed under a bed of a press; a carriage mounted in said ejector-frame for vertical reciprocal movement to and fro relative to the bed of the press; a toggle-linkage pivoted at one end to and suspended from said frame, the other lower end of said linkage being pivoted to and supporting said carriage so that said toggle-linkage is in a straight-line position, when the carriage is in its lowermost position; means for mounting said ejector-frame under the die-bed of the press; an ejector-pad carried by and movable with said carriage and positioned to align with a work-piece on the die-bed of the press to eject the work-piece during the movement of said carriage toward said die-bed; and actuating means for causing the ejecting stroke of the ejector-pad and allowing said carriage and its pad to recede to its lowermost position by gravity after each ejecting stroke, said actuating means being carried by said ejector-frame and positioned and arranged to exert a continuous pressure on the toggle-joint of said linkage to angulate said linkage from its straight-line position periodically for raising said carriage and its ejector-pad from its lowermost position toward the press-bed to eject a work-piece from its die, whereby the maximum initial force of said actuating means is exerted at the beginning of said ejecting stroke and said force progressively decreases during the remainder of said ejecting stroke as the toggle-linkage angulates farther from its straight-line position.

2. A work-piece ejector, as set forth in claim 1, wherein the actuating means includes an oscillatory cam member mounted on a shiftable axis and having its cam surface positioned and formed to exert a continuous pres- 5 sure on said toggle-joint during its angulation of said toggle-linkage and terminating in a dwell which discontinues said angulation; and means for adjusting said axis of said cam member to shift said camming surface and the dwell thereof relative to said toggle-joint for increasing or decreasing the effective camming action and, thus, varying the extent of the ejecting stroke of said carriage, according to the requirement of different work-pieces, while retaining the stopping-point of said angulation constant for any given adjustment of the cam member.

3. In a work-piece ejector for a heavy-duty die-stamping press, particularly of the coining type having a diesupporting bed and a die-ram movable to and fro relative to the bed-die, the improvement comprising an ejector-frame adapted to be disposed under a bed of a press; a carriage mounted in said frame for vertical reciprocal movement to and fro relative to the press bed; a workpiece ejector-pad mounted on said carriage for vertical adjustment relative to said carriage and said press-bed; a toggle-linkage pivotally connected at one of its ends to said ejector-frame near the upper end of said carriage and having its other end pivoted to the lower end portion of said carriage, whereby the carriage is supported by said linkage and the weight of the carriage biases said linkage to its straightened position; and an operable cam member formed and positioned to engage said togglelinkage to intermittently angulate said linkage, causing said carriage and its ejector-pad to move toward the press-bed to eject the work-piece therefrom, and then allowing the carriage to gravitate and straighten said toggle-linkage for another angulation thereof.

4. The subject matter of claim 3 characterised by the cam member being mounted on an axis carried on a link pivoted at one end to said ejector-frame and having its other end slidably adjustable along a rod carried by said frame, whereby the extent of the ejecting stroke may be varied, and means on said cam member adapted to be connected with the actuating means of the press in timed relation with the press operation.

5. A work-piece ejector, for a heavy-duty press of the coining type, comprising a frame adapted to be disposed under a bed of a press; a carriage positioned in and mounted on said frame for vertical reciprocal movement to and fro relative to the press-bed; a work-piece ejectorpad carried by and movable with said carriage and positioned to eject a work-piece from the press-bed and then recede from said bed; a pair of spaced links disposed within said carriage and pivotally suspended at one of their ends from a cross-pin extending through elongated slots in the upper end portion of said carriage and mounted in said frame at its ends; a second pair of spaced links having one of their ends pivotally connected to the free ends of said first pair of links, respectively, and having their other ends pivoted to the lower end portion of said carriage, whereby the carriage is supported by said linkage and the weight of the carriage biases said linkage to its straightened position; a roller disposed centrally between said pairs of links and journalled on the pivots connecting said pairs of links, and a cam member formed and positioned to engage said roller and intermittently angulate said linkage from its straight-line position for raising said carriage and its 70 ejector-pad to eject a work-piece from the bed-die of the press with the maximum initial force being exerted at the beginning of the ejecting stroke and progressively decreasing during the remainder of said ejecting stroke.

(References on following page) References Cited in the file of this' patent UNITED STATES PATENTS Long Sept. 20, 1881 Jones June 28, 1892 Snaith Nov. 15, 1892 Parkinson June 26, 1894 Wilcox Feb. 18, 1919 Limont May 9, 1922 8 Klocke Oct. 6, 1936 Fischer Feb. 29, 1944 Peterson Aug. 8, 1944 Broscomb Apr. 3, 1951 Barkham Sept. 6, 1955 FOREIGN PATENTS Austria Dec. 10, 1925 

